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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,561

If you walk around a board laying on

the ground, you can't see its length

if you are straight in line with it.

Call this the

If you walk around a quarter of a

circle and look at the board

broad side, then you see the length

of the board without any shortening

like on an angle. So call this

. At the

slanted angles in between, it is

still the sine of the angle with the

length of the board vector. I

thought this up because I had

a dream last night where I was

walking away from someone and

I thought to myself, they can't see

my face because of the cosine of

the angle!! When I woke up I

tried to make sense of that!

**igloo** **myrtilles** **fourmis**

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**krassi_holmz****Real Member**- Registered: 2005-12-02
- Posts: 1,908

Interesting dream!

IPBLE: Increasing Performance By Lowering Expectations.

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**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

I think I understand. Are you saying that your eye-level is exactly the same as the level of the board, and so you see it only as a line?

If so, it the line would seem to get bigger as you walked around it and then get smaller again. If the board was rotating instead of you, it would look like some kind of phantom growy-shrinky line.

Why did the vector cross the road?

It wanted to be normal.

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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,561

Yeah, that's what I meant. I guess I should have said you look from eyes that are

on your feet, but I forgot to say that.

**igloo** **myrtilles** **fourmis**

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